I found things got rather hairy when trying to update an existing one that has been in service for a couple of years, just too much has changed in Arch since systemd so I put everything off until I had time to start fresh on all of them using the rootfs provided.
I can gladly report that starting over gave me no specific head scratchers and everything is working great. Hopefully we're clear of major update woes for a while... or I should just learn to leave something that works fine alone.
Well actually for some reason I can't access any of the plugs via smb by hostname any more, not a big deal... not sure what I missed though.